1. Field of the Invention
The invention relates to a fork-lift truck with a hydraulic drive having a hydraulic motor, a power source driving the hydraulic motor and a hydraulic control system driving the power source.
2. Background Art
Such fork-lift trucks for displacing goods are known in many variants. "Transportable" fork-lifts are for instance known which can be fixed to the rear of a goods vehicle. These fork-lift trucks have the drawback that, when the fork-lift truck runs up against an obstacle or when a relatively steep slope is negotiated, the power source is not sufficiently great to provide the required power, i.e. the fork-lift truck is no longer moved forward at the desired speed. The power source, usually a combustion engine or electric motor connected to a pump, is herein overloaded whereby the performance capacity is reduced. In the case of a combustion engine the power source will then finally cut out if the overloading continues. This overload of the power source can only be prevented by reducing the required power. This generally means in practice that a pedal controlling the travel speed must be pressed down less deeply in the case of obstacles as described above.
The invention has for its object to provide a fork-lift truck with a hydraulic drive with which the required power is automatically adjusted downward when the power source is overloaded.